I'd skip on the 20" and get the adaptive drive. I have both and the cost of replacing the tires on the 20's vs the 19's seals the deal for me on my net diesel order. The AD is worth the money in my book if you want a great handling X5. Good luck!

Thx. Added both. We really like the 20s and I'm willing to put up with the cost and implications of staggered (mostly makes rotation more painful). We will hate running around on 18s all winter long. Looking for a set of 18" take offs now.